This two-digit digital pressure gauge was found in the 1992 special edition of Radio Electronics Experimenter. A/D converter integrated circuits are uncommon today.
This filter can be used to eliminate hum in sound equipment. Operational amplifiers can be 741 and...
This signal amplifier for ATV in the 427 to 439 MHz band was found in a magazine 73 for radio...
This simple three-LED sensor uses an NTC at the input. The circuit is based on an uncommon...